Mail Archives: geda-user/2014/03/29/16:48:33
On Saturday 29 March 2014, Stephen R. Besch wrote:
> On 03/29/2014 04:03 PM, al davis wrote:
> > On Saturday 29 March 2014, Stephen R. Besch wrote:
> >> realizing that I had forgotten
> >> about the sign bit it became clear that you cannot just
> >> toss the high bits - you need to toss the low bits
> >> (essentially an integer divide by 16).
> >
> > Usually if numbers are small enough, you can toss the high
> > bits.
> >
> > "Usually" means the usual two's complement representation.
>
> True enough as long as they are all positive. With signed
> data, you really have no choice but division of some kind
True even with negative numbers, assuming the usual "two's
complement" representation. Even with other representations the
conversion is usually simple.
If the number is "small enough" and positive, the high bits are
all zero. If negative, the high bits are all 1, and after
tossing the high bits are still all 1.
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